Workshop Practice (ME192)

Transcription

1 Workshop Practice (ME192) Credits: 3 Contacts: Mail: poddar05@gmail.com Web:

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4 Exp 03: To make a pin as given profile from a φ20 mm mild steel rod in a lathe. Material Required: mild steel bar of φ35 mm Tool and Accessories required: Lathe machine, 3-jaw chuck, facing tool, turning tool, grooving tool, chamfering tool, marking and measurement tool, combination drill Drawing: job or Pin profile to be made

5 Procedures: Select the speed, feed and depth of cut for different operations Load the job on three jaw chuck Perform facing operation on both end of the job by a combination drill Hold the job between centers using lathe dog Turn the job to reduce diameter to φ x1 mm over length of L1 mm and to φ x2 mm by a turning tool Chamfering one end by chamfering tool Grooving at required position by using grooving tool Check the dimensions Precautions: Conclusion:

6 Lathe: A Lathe is an important and oldest known machine tool in any workshop. The job to be machined is held and rotated in a chuck, face plate, catch plate, between centres etc. A suitable cutting tool is advanced against rotating job. Since the cutting tool material is harder than the workpiece, the metal is easily removed from the job in the form of chip. Cutting tool used is a single point cutting tool. Common operations performed on lathe machine: Some common operations are facing, turning, chamfering, parting off, drilling, knurling, boring, thread cutting etc Cutting speed, feed and depth of cut: Cutting speed(v) : The cutting speed is the distance travelled by a point on the outer surface of the work in one minute. It is expressed in meters per minute. or The Peripheral Speed of Workpiece past the Cutting Tool V = πdn/1000 m/min where D is the diameter of the work in mm N is the r.p.m. of the work Feed: The feed of a cutting tool in a lathe work is the distance the tool advances for each revolution of the work. Feed is expressed in millimeters per revolution.

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8 Depth of cut: The depth of cut is the perpendicular distance measured from the machined surface to the uncut surface of the workpiece. It is expressed in millimeters. In a lathe, the depth of cut is expressed as follows Depth of cut = (D1 D2) / 2 Where D1- diameter of the work surface before machining D2 - diameter of the machined surface Three-jaw chuck: - For holding cylindrical stock centered. - For facing/center drilling the end of your aluminum stock D1 D2 f Feed D1 D2 d Depth of Cut

9 3 Operating Conditions Cutting speed Workpiece N Chuck Feed (f ) Tool Depth of cut (d) Machined surface Chip Depth of cut

10 Operations on Lathe.. Turning Facing knurling Grooving Parting Chamfering Taper turning Drilling Threading

11 Operations on Lathe.. Cutting speed Chuck N Turning.. Cylindrical job Workpiece Depth of cut (d) Machined surface Feed Chip Tool Depth of cut

12 Operations on Lathe.. Turning.. Excess Material is removed reduce Diameter Cutting Tool: Turning Tool a depth of cut of 1 mm will reduce diameter by 2 mm to

13 Operations on Lathe.. Chuck Cutting speed Facing Flat Surface/Reduce length Workpiece Tool d Machined Face Feed Depth of cut

14 Operations on Lathe.. Facing.. machine end of job Flat surface or to Reduce Length of Job Turning Tool Feed: in direction perpendicular to workpiece axis Length of Tool Travel = radius of workpiece Depth of Cut: in direction parallel to workpiece axis

15 Operations on Lathe.. Grooving Produces a Groove on workpiece Shape of tool shape of groove Carried out using Grooving Tool A form tool Also called Form Turning

16 Operations on Lathe.. Grooving.. Shape produced by form tool Groove Form tool Feed or depth of cut Grooving tool

17 Operations on Lathe.. Parting Cutting workpiece into Two Similar to grooving Parting Tool Tool rides over at slow feed Coolant use

18 Operations on Lathe.. Chamfering Chamfer Feed Chamfering tool

19 Operations on Lathe.. Chamfering Beveling sharp machined edges Similar to form turning Chamfering tool 45 To Avoid Sharp Edges Make Assembly Easier

20 SINGAL POINT CUTTING TOOL FOR LATHE

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22 DIFFERENT LATHE OPERATIONS

23 FORM TOOL

24 References Books work shop Technolgy by Hajra choudry Advances in Manufacturing Technology C.J Thomas